Interface Configuration Guide 7705 SAR Interfaces
Edition: 01 3HE 11011 AAAC TQZZA 59
3.1.3.12.1 Rate Limiting
The 7705 SAR supports egress-rate limiting and ingress-rate limiting on Ethernet
ports.
The egress rate is set at the port level in the config>port>ethernet context.
Egress-rate limiting sets a limit on the amount of traffic that can leave the port to
control the total bandwidth on the interface. If the egress-rate limit is reached, the
port applies backpressure on the queues, which stops the flow of traffic until the
queue buffers are emptied. This feature is useful in scenarios where there is a fixed
amount of bandwidth; for example, a mobile operator who has leased a fixed amount
of bandwidth from the service provider.
The ingress-rate command configures a policing action to rate-limit the ingress
traffic. Ingress-rate enforcement uses dedicated hardware for rate limiting; however,
software configuration is required at the port level (ingress-rate limiter) to ensure that
the network processor or the adapter card or port never receives more traffic than
they are optimized for.
The configured ingress rate ensures that the network processor does not receive
traffic greater than this configured value on a per-port basis. Once the ingress-rate
value is reached, all subsequent frames are dropped. The ingress-rate limiter drops
excess traffic without determining whether the traffic has a higher or lower priority.
3.1.3.12.2 Access Ports
Access ports on the following can be configured for PPP/MLPPP channel groups:
• 2-port OC3/STM1 Channelized Adapter card
• 16-port T1/E1 ASAP Adapter card
• 32-port T1/E1 ASAP Adapter card
• T1/E1 ports on the 4-port T1/E1 and RS-232 Combination module (on
7705 SAR-H)
• T1/E1 ports on the 7705 SAR-A (variants with T1/E1 ports)
• T1/E1 ports on the 7705 SAR-M (variants with T1/E1 ports)
• T1/E1 ports on the 7705 SAR-X
Customer IP traffic can be transported directly over PPP or MLPPP links. Access
ports on the following can also be configured for TDM to transport 2G traffic from
BTSs or ATM/IMA to transport 3G UMTS traffic from Node Bs:
• 2-port OC3/STM1 Channelized Adapter card
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